1. Field of the Invention
This invention relates to a multi-type liquid droplet forming apparatus which ejects a liquid in a form of droplet from a plurality of orifices closely spaced to each other, and more particularly, to a multi-type liquid droplet forming apparatus for an ink jet recording process.
2. Description of the Prior Art
Among various known recording systems, one of the very useful recording systems is a so-called ink jet recording system which is a kind of non-impact recording system substantially free from noise and can effect a high speed recording and also can record on plain paper without any particular fixing treatment. Heretofore, there have been proposed various ink jet recording processes and some are improved to use practically while some are still under development.
The ink jet recording process comprises projecting a liquid droplet, so-called ink, toward and attaching it to a record receiving member such as paper. Liquid droplet forming systems for ink jet recording process may be classified on the basis of the method of forming the droplet and the means for controlling the direction of projection of the droplet.
One representative system is that as disclosed, for example, in U.S. Pat. Nos. 3,596,275 and 3,298,030, that is, a liquid droplet stream of a controlled electric charge amount is produced by a continuous vibrating method and projected between deflection electrodes where a uniform electric field is present, and thus the trajectory of droplets is controlled so as to attach the droplets to a record receiving member. This system is generally called a "continuous system".
Another representative system is, for example, that disclosed in U.S. Pat. No. 3,747,120. A recording head having an orifice ejecting liquid droplets for recording is provided with a piezoelectric vibrator to which electric signals are applied on demand to convert the electric signals to mechanical vibration resulting in ejection of liquid droplets from the orifice to project them toward and attach them to a record receiving member. This is the so-called "on-demand system".
When the above mentioned ink jet recording processes are conducted by scanning by a single orifice head, a high speed recording is difficult because the scanning takes a lot of time. Therefore, the so-called multi-type system is recognized as an advantageous one for high speed recording. According to the multi-type system, the ink droplet ejecting orifices are arranged in the form of multi-array and a recording corresponding to a predetermined width or area is effected at once.
There are known various problems with using the ink jet recording technique as a multi-array system. Among them, the most serious problem is that quality of the recorded letters or signs can be hardly kept at a high grade.
In other words, a multi-type ink droplet forming apparatus where a number of actuating chambers having ink droplet ejecting orifices are assembled at a high density, cross talk is liable to often occur and an ink droplet may be ejected from an actuating chamber to which a signal is not applied because said actuating chamber is affected by an input signal to the adjacent actuating chamber or there occurs an interference between adjacent chambers as to the ink ejecting actin. As the result, the recorded letters or signs often suffer from smudge, defect portion, or irregularity.